Halogenated acetylenes as fuel components



Patented Sept. 28, 1954 STATES HALOGENATED ACETYLENES' AS FUEL COMPONENTS No Drawing. Application March 8, 1951, Serial No. 214,622

(Granted under Title 35, U. S. Code (1952), see. 266) Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to fuels and more particularly to fuels for air jet propulsion, containing halogenated acetylenes.

The problem of maintaining combustion in a stream of gas having a high velocity such as arises in connection with air jet propulsion can be approached in two ways.

(1) By designing devices called fiameholders which create a local slowdown or recirculation of the air flow;

(2) By developing fuels highly reactive as regards oxidation thus reducing the ignition lag of the fuel. The second procedure offers advantage in that any advance in fuel chemistry simplifies mechanical design. It is accordingly an object of our invention to develop an easily ignited fuel. A second object of our invention is to develop an easily ignited fuel for use in jet and ram-jet engines.

One disadvantage associated with many of the highly reactive fuels, especially those containing inorganic components such as aluminum, boron and silicon, is the residue of ash left as a product of combustion. A third object of our invention is therefore to produce a reactive fuel which produces only gaseous combustion products. Other objects will be evident from the following description.

The highest reactivity in oxidation is found among the substances, described as hypergolic, which ignite spontaneously upon coming in contact with air. Most of these substances are too expensive to be used in the pure state. Many as mentioned above create solid combustion products which tend to clog injection systems or form deposits on the chamber walls.

We have found that, the halogenated acetylenes are compounds with properties suitable for use in fuels of the type desired. The dichloro and dibromo compounds are especially useful. Their pertinent properties are as follows:

CzCl2sp. gr. 1.26; B. P. 33 C. at 760 mm Hg C2Br2-sp. gr. 2.20; B. P. 72 C. at 760 mm Hg These compounds are incendiaries which decompose explosively on the slightest contact with air. Synthesized by passing acetylene through alkali hypochlochlorite or hypobromite solutions at 10W 2 temperature, their manufacture is cheap and easy to carry out.

This bromide and the chloride are miscible with hydrocarbons, imparting their spontaneously igniting properties thereto. A mixture of 50 parts of gasoline and 50 parts dichloro acetylene was found to be self-igniting in air at normal temperatures. The proportion can be varied to yield the igniting properties desired. As little as 10% by weight of either the dibromo or dichloro acetylene yields an increase in the rate of combustibility over that of straight fuel, particularly at elevated temperatures. Higher percentages of either compound can as shown increase the beneficial effect up to spontaneous ignitibility. Other such compounds may of course be employed. By adapting the concentration of the halogenated acetylenes in the fuel to the prevailing conditions in the propulsion unit, it is possible to activate the combustion process and thus improve performance.

The halogenated acetylenes have remarkable advantages in comparison with other spontaneous fuels such as boranes and the metal alkyls or aryls. Since the products of complete oxidation are all volatile at normal temperature and pressure no difficulties are encountered with the nozzles by formation of solid reaction products such as B203. Difficulties always arise with such compounds unless complex constructions or injection systems are adopted. The production costs, furthermore, of these acetylenes are much lower than for most of the other fuel components mentioned. Not only is the synthesis of the chloride or bromide simplicity itself, but also the raw materials required are readily available and cheap in price.

What we claim is:

1. A liquid fuel composition comprising gasoline and at least 10 per cent of a halogenated acetylene, based on the amount of gasoline presen 2. The composition of claim 1 in which the halogenated acetylene is dichloroacetylene.

3. The composition of claim 1 in which the halogenated acetylene is dibromacetylene.

4. A liquid fuel composition comprising equal portions of gasoline and a halogenated acetylene.

5. The composition of claim 4 in which the halogenated acetylene is one selected from the group consisting of dichl'oroacetylene and dibromacetylene.

6. The composition of claim 4 in which the halogenated acetylene is dichloroacetylene.

7. The composition of claim 4 in which the halogenated acetylene is dibromoacetylene.

8. A liquid fuel composition comprising gasoline and at least 50 per cent of a halogenated acetylene based on the amount of gasoline present.

9. The composition of claim 8 in which the halogenated acetylene is dichloroacetylene.

10. The composition of claim 8 in which the halogenated acetylene is dibromoacetylene.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 5 2,065,588 Howes Dec. 29, 1936 2,490,606 Williams et a1. Dec. 6, 1949 OTHER REFERENCES Huntress: Organic Chlorine Compounds, John 10 Wiley & Sons, London, England (1948), page 522.

Copy in Scientific Library. 

1. LIQUID FUEL COMPOSITION COMPRISING GASOLINE AND AT LEAST 10 PER CENT OF A HALOGENATED ACETYLENE, BASED ON THE AMOUNT OF GASOLINE PRESENT. 